The preparation and use of 2-amino-5-halo-6-alkyl-4-pyrimidinols as antiviral agents is known (U.S. Pat. No. 3,956,302 and Nichols, Weed and Underwood, Antimicrobial Agents and Chemotherapy 9,433, 1976). Preparation of 2-amino-5-bromo-6-phenyl-4-pyrimidinol (V, where X.sub.3 is Br and X.sub.1 is phenyl) has been reported (Brown and Stevens, JCS Perkin I, 1023, 1975) but no utility has been described for this material. Snell, Elias and Freeman in GB Pat. No. 1,223,686 (1967) disclose a variety of 5,6-disubstituted 2-amino-4-pyrimidinols, such as 2-dimethylamino-5-bromo-6-methyl-4-pyrimidinol. Various 5-unsubstituted 2-amino-6-arylpyrimidinols are known (e.g., Shirahawa, Yakuyaku Fasshi 50, 1562, 1960 (CA 55, 10651b); Kulkarui et al., J. Sci. and Ind. Res. Indil. 19C, 6, 1960; and U.S. Pat. No. 2,776,283. Diuretics and cardioregulatory properties are described for various 2-amino and 2-substituted amino-5aminomethyl and 5-aryl-6-aryl-4-pyrimidinols, U.S. Pat. Nos. 2,704,285, 2,723,777 and 2,776,283.